$ python3 my_dfs.py 
頂点5から頂点7への経路: 5 2 1 0 7 
0, adj = {1, 7}, 2, 3, 6, 1
1, adj = {0, 2, 6}, 2, 2, 9, 2
2, adj = {1, 3, 5}, 2, 1, 14, 5
3, adj = {2, 4, 5}, 2, 10, 13, 2
4, adj = {3, 5}, 2, 11, 12, 3
5, adj = {2, 3, 4, 6}, 2, 0, 15, None
6, adj = {1, 5}, 2, 7, 8, 1
7, adj = {0}, 2, 4, 5, 0